Question

Срочно. Среди 50 лотерейных билетов есть 5 выигрышных. Найти вероятность того, что 2 наугад выбранных билета окажутся выигрышными. Можно, пожалуйста, с пошаговым объяснением и формулами. Надо срочно. Спасибо

Answer 1

5/50=1/10 вероятность одного выигрышного билета.
1/10*1/10=0,01 вероятность двух выигрышных билетов

Answer 2

To find the probability of selecting 2 winning tickets out of 50 lottery tickets, we can use the concept of combinations. The formula for calculating combinations is:

nCr = n! / (r! * (n-r)!)

Where: - n is the total number of items (in this case, the total number of lottery tickets) - r is the number of items to be chosen (in this case, the number of winning tickets to be chosen)

In this case, we have 50 lottery tickets and we want to choose 2 winning tickets. So, n = 50 and r = 2.

Let's calculate the probability step by step:

Step 1: Calculate the total number of combinations

Using the formula for combinations, we can calculate the total number of ways to choose 2 tickets out of 50:

50C2 = 50! / (2! * (50-2)!)

Simplifying this expression:

50C2 = 50! / (2! * 48!)

Step 2: Calculate the number of favorable outcomes

In this case, the favorable outcomes are the number of ways to choose 2 winning tickets out of 5. So, we need to calculate:

5C2 = 5! / (2! * (5-2)!)

Simplifying this expression:

5C2 = 5! / (2! * 3!)

Step 3: Calculate the probability

The probability of selecting 2 winning tickets out of 50 can be calculated by dividing the number of favorable outcomes by the total number of combinations:

Probability = Number of favorable outcomes / Total number of combinations

Substituting the values we calculated in Step 1 and Step 2:

Probability = (5! / (2! * 3!)) / (50! / (2! * 48!))

Simplifying this expression:

Probability = (5! * (2! * 48!)) / (2! * 3! * 50!)

Now, let's calculate the probability using the given formula:

Calculation:

```python import math

total_combinations = math.factorial(50) / (math.factorial(2) * math.factorial(50-2)) favorable_outcomes = math.factorial(5) / (math.factorial(2) * math.factorial(5-2))

probability = favorable_outcomes / total_combinations probability ```

The probability of selecting 2 winning tickets out of 50 is approximately 0.008 or 0.8%.

Please note that this calculation assumes that each ticket has an equal chance of being a winning ticket and that the selection is done randomly.